Very recently we had demonstrated by a 13C-NMR study that the long-acting opiate drugs naloxone hydrazone, naltrexone hydrazone, and oxymorphone hydrazone exist as mixtures of their anti and syn isomers. That finding inicated that the corresponding opiate azines, which are formed from the above hydrazones, and which are much longer acting than these hydrazones, may exist theoretically as three possible isomers -- anti-anti, anti-syn, and syn-syn. Our recent preliminary 13C-NMR studies of the above opiate azines revealed that indeed they exist as mixtures of all three isomers. In these azine isomers the two opiate units of the azines have different geometric and steric dispositions, which may be of a great importance for their interaction with the opiate receptor. We propose to separate these azine isomers and to determine their configuration via the X-ray structural study. In order to understand the mechanism of action of the opiate azines and to properly map the opiate receptor it is essential to establish the relative activities of the three azine isomers. The pure azine isomers, when separated, will be tested for their opiate activities in vivo and in vitro. These biological testings are not the part of this proposal and thus are not discussed here. In summary, the objective of this proposed study is to contribute toward elucidation of the mechanism of the molecular action of the long-acting opiate antagonist naloxone azine and its analogues.